Method of preparing fiber-reactive formazan dyes involving hydrolysis of a formyl amino moiety

ABSTRACT

Fiber-reactive formazan dyes are prepared by diazotizing a protectively formylated hydroxyphenylenediamine, coupling with a hydrazone compound, metallizing, eliminating the protective group, and reacting with a halotriazine and optionally thereafter with an amine or a hydroxy compound via novel aminophenol intermediates.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a novel process for preparingfiber-reactive formazan dyes by diazotizing a protectedhydroxyphenylenediamine compound, coupling with a hydrazone compound,metallizing, eliminating the protective group, and reacting with ahalotriazine and optionally thereafter with an amine or a hydroxycompound. The present invention also relates to novel aminophenols.

2. Description of the Background

EP-A-280 139 discloses preparing aminoformazan dyes by reacting thearylhydrazone with a diazotized o-hydroxyaminobenzene. Amino groups tobe present in the end, product must be protectively acetylated beforethe reaction and the protective acetyl group must be reeliminatedafterwards.

However, the alkaline hydrolysis of the protective group requires highalkali concentrations, high reaction temperatures and long reactiontimes.

A further disadvantage of existing processes is that, prior to thereaction with hydrolysis-sensitive fiber-reactive components, eg. withhalotriazines, the alkaline solution must first be neutralized, whichproduces appreciable amounts of salt.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an economically andecologically improved process for preparing aminoformazan compoundswhich avoids the problems mentioned and makes possible the synthesis ofaminoformazan compounds and their further reaction to form reactive dyesin a high space-time yield.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

We have found that this object is achieved by a process for preparingfiber-reactive-formazan dyes which in the form of the free acid conformto the formula I ##STR1## where cat.sup.⊕ is one equivalent of a cation,

n is 1 or 2,

X is oxygen or a radical of the formula CO--O or SO₂ --O,

Me is copper or nickel,

Y is halogen,

Z for n=1 is halogen, C₁ -C₄ -alkoxy, amino, mono- or di(C₁ -C₄-alkyl)amino, substituted C₂ -C₄ -alkylamino or phenyl- or N-(C₁-C₄)-N-phenyl-amino, wherein the phenyl group may in each case besubstituted, or for n=2 is a radical of the formula ##STR2## where L isC₂ -C₆ -alkylene or unsubstituted or hydroxysulfonyl-substitutedphenylene and Y is as defined above, and

the-rings A, B and C may carry further substituents, which comprises

a) as step 1 diazotizing an aminophenol of the formula II ##STR3## wherethe ring C is as defined above, coupling with a coupling component ofthe formula III ##STR4## where X and the rings A and B are each asdefined above, and before, during or after the coupling reaction addinga copper or nickel salt,

b) as step 2 hydrolyzing the resulting formazan compound of the formulaIV ##STR5## where cat.sup.⊕, X, Me and the rings A, B and C are each asdefined above, under acid or base catalysis, and

c) as step 3 reacting the resulting amino compound with a halotriazineof the formula Va or Vb ##STR6## where Y is in either case as definedabove and Z¹ is C₁ -C₄ -alkoxy, amino, mono- or di(C₁ -C₄ -alkyl)amino,substituted C₂ -C₄ -alkylamino, phenyl- or N- (C₁ -C₄ -alkyl)-N-phenyl-amino, wherein the phenyl group may in either case besubstituted, or a radical of the formula ##STR7## where L and Y are eachas defined above.

cat.sup.⊕ is one equivalent of a cation. It is either a proton orderived from metal or ammonium ions. Metal ions are in particular thelithium, sodium or potassium ions. Ammonium ions for the purposes of thepresent invention are substituted or unsubstituted ammonium cations.Substituted ammonium cations are for example monoalkyl-, dialkyl-,trialkyl-, tetralkyl- or benzyltrialkyl-ammonium cations or thosecations that are derived from nitrogen-containing five- or six-memberedsaturated heterocycles, such as pyrrolidinium, piperidinium,morpholinium, piperazinium or N-alkylpiperazinium cations or theirN-monoalkyl- or N,N-dialkyl-substituted products. Alkyl is here to beunderstood as meaning in general straight-chain or branched C₁ -C₂₀-alkyl, which may be substituted by hydroxyl groups and/or interruptedby oxygen atoms in ether function.

Particularly noteworthy cations are protons and lithium, sodium andpotassium ions.

The rings A, B and/or C in the formula I may have as furthersubstituents for-example halogen, in particular chlorine or bromine, orhydroxysulfonyl, and then generally have one or two such substituents.

A substituted phenylamino Z in the formula I may have as substituentsfor example hydroxysulfonyl, 2-sulfatoethylsulfonyl,2-chloroethylsulfonyl, 3-(2-sulfatoethylsulfonyl)propanoylamino,3-(2-chloroethylsulfonyl)propanoylamino,4-(2-sulfatoethylsulfonyl)butyrylamino or4-(2-chloroethylsulfonyl)butyrylamino. The phenyl ring is then generallymonosubstituted or disubstituted.

A substituted C₂ -C₄ -alkylamino Z in the formula I may have assubstituents for example hydroxysulfonyl, 2-sulfatoethylsulfonyl or2-chloroethylsulfonyl.

Y and Z are each for example fluorine, chlorine or bromine.

Z may also be for example methoxy, ethoxy, propoxy, isopropoxy, butoxy,isobutoxy, sec-butoxy, mono- or dimethylamino, mono- or diethylamino,mono- or dipropylamino, mono- or diisopropylamino, mono- ordibutylamino, N-methyl-N-ethylamino, 2-hydroxysulfonylethylamino,2-chloroethylsulfonylamino, phenylamino, 2-, 3- or4-hydroxysulfonylphenylamino, 3- or4-(2-sulfatoethylsulfonyl)phenylamino, 3- or 4-(2-chloroethylsulfonyl)phenylamino, N-methyl- orN-ethyl-N-[4-(2-sulfatoethylsulfonyl)phenyl]amino, 3- or4-[4-(2-sulfatoethylsulfonyl)butyrylamino]phenylamino or 3- or4-[4-(2-chloroethylsulfonyl)butyrylamino]phenylamino.

L is for example (CH₂)₂, (CH₂)₃, (CH₂)₄, (CH₂)₅, (CH₂)₆, CH(CH₃)CH₂,CH(CH₃)CH(CH₃), 1,2-, 1,3- or 1,4-phenylene or4-hydroxysulfonyl-1,3-phenylene.

Suitable copper or nickel salts for addition in reaction step 1 are ingeneral divalent salts, such as cupric sulfate, cuptic chloride, cupricacetate, nickel chloride, nickel sulfate or nickel-acetate.

The process of the invention is advantageously carried out bydiazotizing the aminophenol II in step 1 in a conventional manner, forexample in an aqueous medium, with sodium or potassium nitrite in thepresence of a mineral acid, for example hydrochloric acid or sulfuricacid, at from 0° to 10° C., or in an organic solvent at from 0° to 10°C. with nitrous esters or glycols as diazotizing reagent. Theresulting-diazonium salt is then added, usually as a solution orsuspension, to the coupling component III in an aqueous medium. Thecoupling is in general carried out at from 10° to 25° C. and at pH 6-10.Before, during or after the coupling reaction the reaction mixture hasadditionally added to it a copper or nickel salt.

Following a subsequent stirring phase at from 10° to 25° C. for about1-4 hours, the formation of the formazan IV is complete.

Per mole of aminophenol II the amounts used are in general from 1.0 to1.1 mol of diazotizing reagent, from 0.9 to 1.1 mol of couplingcomponent III and from 0.9 to 1.2 mol of copper or nickel salt.

The formazan IV can either be isolated ( for example by salting out) orhydrolyzed directly in the reaction solution under acid or basecatalysis.

An acid-catalyzed hydrolysis as step 2 is in general carried out at a pHof from 1 to 3, preferably from 1 to 2, and at from 40° to 80° C. in anaqueous medium. The acid used can be for example a mineral acid, such ashydrochloric acid, sulfuric acid or phosphoric acid. The amount of acidused per mole of formazan IV is in general about 2 mol equivalent.

A base-catalyzed hydrolysis is in general carried out in an aqueousmedium at a pH of from 8 to 12, preferably from 10 to 11, and at from40° to 80° C. The base used can be for example an aqueous solution (from1 to 20% strength by weight ) of lithium, sodium or potassium hydroxide.The amount of base used per mole of formazan IV is in general from 3 to12 mol equivalent.

Hydrolysis is complete after 0.5-2 h.

The subsequent step 3 comprises reacting the resulting amino compound ofthe formula IVa ##STR8## where cat.sup.⊕, X, Me and the rings A, B and Care each as defined above, with the triazine of the formula Va or Vb.For this the reaction solution is cooled down to room temperature andadjusted to a pH of 4-6. Then triazine Va or Vb is added. The pH of thereaction mixture is at the time maintained, for example with sodiumbicarbonate, at from 4 to 4.5 and at from 0° to 25° C.

To prepare those compounds of the formula I where n is 2, the aminocompound of the formula IVa is reacted with the triazine of the formulaVb where Z¹ is the abovementioned radical of the formula ##STR9## in amolar ratio of from 1.9:1 to 2.1:1.

When the reaction is carried out with the triazine of the formula Va, itis also possible to carry out a subsequent reaction with a compound ofthe formula VI

    Z.sup.2 --H                                                (VI)

where Z² is C₁ -C₄ -alkoxy, amino, mono- or di(C₁ -C₄ -alkyl )amino,substituted C₂ -C₄ -alkylamino or phenyl- or N-(C₁ -C₄-alkyl)-N-phenyl-amino, wherein the phenyl group may in either case besubstituted. For this purpose the reaction mixture is admixed with from1.0 to 1.2 mol of the compound VI, based on 1 mol of triazine Va, andsubsequently stirred at from 40° to 60° C. and at a pH of 5.0 to 6.5,which may be set for example with sodium bicarbonate, for 1-8 hours.

After the reaction has ended, the dye can be isolated in a conventionalmanner, for example by spray drying or salting out.

Preference is given to employing the process for preparing formazan dyesof the formula I where two of the rings A, B and C are eachmonosubstituted by hydroxysulfonyl.

Preference is further given to employing the process for preparingformazan dyes of the formula I where Me is copper.

Preference is further given to employing the process for preparingformazan dyes of the formula I where Y is fluorine or chlorine, inparticular chlorine.

The present invention further provides aminophenols of the formula II##STR10## where the ring C can be substituted. Suitable substituents arefor example those mentioned above by way of example.

As will be evident from the above observations, the aminophenols II areuseful intermediates for the process of the invention.

They are prepared in a conventional manner. One method comprises forexample formylating a nitrophenol of the formula IIa ##STR11## where thering C is as defined above, with formic acid in an aqueous medium andthen catalytically reducing the nitro group.

The amount of formic acid used in the formylation is in general from 1to 15 mol per mole of nitrophenol IIa. The formylation itself is ingeneral carried out at pH 1-5, preferably pH 2-3, and at from 30° to 80°C., preferably at from 35° to 50° C.

The other compounds employed in the process of the invention are knownper se and described for example in the art cited at the beginning.

The advantage of the novel process is that the formazan dyes of theformula I can be prepared in a simple manner and in high purity andspace-time yield. Compared with the hydrolysis of the protective acetylgroup, which is very difficult to carry out, the formyl group can beeliminated under very mild conditions by both acid and alkalinehydrolysis.

The formazan dyes of the formula I are useful reactive dyes which areadvantageous for dyeing or printing hydroxyl- or nitrogen-containingorganic substrates. Such substrates include for example leather or fibermaterial that contains predominantly natural or synthetic polyamides ornatural or regenerated cellulose. The dyes prepared by the novel processare preferable for dyeing and printing textile material based on cotton.

Embodiments of the invention will now be more particularly described byway of example.

EXAMPLE 1

a) 104.4 g of 2-formylamino-6-aminophenol-4-sulfonic acid were dissolvedin 500 ml of water and adjusted with concentrated hydrochloric acid to

a pH 2-2.3. Then 128 g of 23% strength by weight aqueous sodium nitritesolution were added at from 0° to 5° C. for diazotization. Thereafterexcess nitrite was destroyed with 2 g of amidosulfuric acid.

The resulting diazonium suspension was added at from 10° to 15° C. to amixture, adjusted to pH 6.5 to 7.0, of 144.0 g of hydrazone of theformula ##STR12## and 117.6 g of copper sulfate×5H₂ O in 590 ml of waterwhile the pH is maintained at from 6.5 to7.0. On completion of theaddition the mixture was subsequently stirred at from 15° to 20° C. for2 hours, at which point 300 g of sodium chloride were added. Thesalted-out product was filtered off and dried at 50° C. under reducedpressure, leaving 400 g of an

electrolyte-containing compound of the formula ##STR13##

b1) 50 g of the compound obtained under a) were dissolved in 250 ml ofwater. The solution was adjusted to pH 1 with concentrated hydrochloricacid, then heated to 40°-45° C. and stirred at that temperature untilelimination of the protective formyl group was complete (TLC), whichtook about 4 hours.

After cooling down to room temperature the reaction mixture was adjustedto pH 6.0-6.5 with sodium carbonate and the product was salted out with100 g of sodium chloride. Drying left 61 g of the electrolyte-containingcompound of the formula ##STR14##

b2) 50 g of the compound obtained under a) were dissolved in 250 ml of5% strength by weight sodium hydroxide solution and heated to 60° C. Themixture was subsequently stirred at that temperature for 30 minutes(average time TLC indicated complete elimination of the protectivegroup). The reaction mixture was then cooled down to room temperatureand brought to pH 6.0-6.5 with concentrated hydrochloric acid. Saltingout, filtration and drying under reduced pressure at 50° C. left 63 g ofthe electrolyte-containing compound of the formula ##STR15##

The same method gives the formazans listed below in Table 1.

                  TABLE 1                                                         ______________________________________                                        Example                                                                       No.    Copper formazan                                                        ______________________________________                                         ##STR16##                                                                    3                                                                              ##STR17##                                                                    4                                                                              ##STR18##                                                                    5                                                                              ##STR19##                                                                    ______________________________________                                    

EXAMPLE 6

The reaction solution obtained in Example 1a) before salting out wasbrought to pH 1 with concentrated hydrochloric acid and then heated to40°-45° C. It was subsequently stirred at that temperature for 4 hours,at which point the pH was raised to 4.0-4.5 with solid sodium carbonate.

After cooling down to room temperature, 83.0 g of cyanuric chloride wereadded. The pH of the reaction mixture was maintained at 4.0 to 4.5 withsodium bicarbonate until the acylation had ended. After 2 hours 80 g of3-aminobenzenesulfonic acid, dissolved in 150 ml of water, were added.The suspension was heated to 40° to C. and maintained at pH 6.0-6.5 withsodium bicarbonate.

After 6 hours the formazan dye of the formula ##STR20## was isolated bysalting out.

The same method gives the formazan dyes of the formula ##STR21## listedbelow in Table 2.

                  TABLE 2                                                         ______________________________________                                             Posi-                                                                         tion of                                                                  Ex.  SO.sub.3 H                                                               No.  group   R.sup.1 R.sup.2                                                                           R.sup.3                                              ______________________________________                                         7   5       H       F                                                                                  ##STR22##                                            8   4       H       Cl                                                                                 ##STR23##                                            9   4       H       Cl                                                                                 ##STR24##                                           10   4       H       Cl                                                                                 ##STR25##                                           11   4       SO.sub.3 H                                                                            Cl                                                                                 ##STR26##                                           12   5       H       F   HNC.sub.2 H.sub.4 SO.sub.2 C.sub.2 H.sub.4 Cl        13   4       SO.sub.3 H                                                                            Cl  HNC.sub.2 H.sub.4 SO.sub.3 H                         ______________________________________                                    

EXAMPLE 14

Example 6 was repeated replacing the 3-amino-benzenesulfonic acid by45.5 g of 4-amino-2-methylamino-benzenesulfonic acid dissolved in 100 mlof water.

The suspension was heated to 60° C. and the pH was maintained at from7.0 to 7.5 with sodium bicarbonate. After 6 hours the reaction mixturewas spray dried to isolate the electrolyte-containing formazan dye whichin the form of the free acid conforms to the following formula:##STR27##

EXAMPLE 15

a) 233.5 g of 2-amino-6-nitrophenol-4-sulfonic acid were dissolved in 1l of water at 60° C. The pH was set to 2 with sodium carbonate. Then234.7 g of formic acid were added dropwise in the course of 30 minutesduring which the pH was held at 2 with 50% strength by weight sodiumhydroxide solution.

The reaction mixture was subsequently stirred at 60° C. for 4 hours. Itwas then cooled down to 0°-5° C. and adjusted to pH 6.8 with 50%strength by weight sodium hydroxide solution, and the precipitatedproduct was filtered off with suction. Drying under reduced pressure at60° C. left 466.8 g of the electrolyte-containing compound of theformula ##STR28## (Purity as per HPLC: 97%) ¹ H NMR [d⁶ -DMSO]: δ=7.9,8.4 (aromatic H, CHO), 9.5 (NH) ppm.

b) 465 g of the formylated nitro compound obtained under a) weresuspended in 1.4 1 of water and, after 15 g of Raney nickel were added,hydrogenated with hydrogen (hydrogen pressure: 2 bar) at roomtemperature. After the absorption of hydrogen had ended, the catalystwas filtered off and the mother liquor was freed of solvent. This left460 g of the electrolyte-containing compound of the formula ##STR29##which can be used for dye syntheses without further purification.

We claim:
 1. A process of preparing a fiber-reactive formazan dye whichin the form of the free acid conforms to the formula (I):wherein cat⊕ isone equivalent of a cation, n is 1 or 2, X is oxygen or a radical of theformula CO--O or SO₂ --O, Me is copper or nickel, Y is halogen, Z when nis 1, is halogen, C₁ -C₄ -alkoxy, amino, mono- or di-(C₁ -C₄-alkyl)amino, substituted C₂ -C₄ -alkylamino substituted byhydroxysulfonyl, 2-sulfatoethylsulfonyl or 2-chloroethylsulfonyl; phenylor N-(C₁ -C₄ -alkyl)-N-phenylamino, where each of said phenyl groups isunsubstituted or substituted by hydroxysulfonyl, 2-sulfatoethylsulfonyl,2-chloroethylsulfonyl, 3-(2-sulfatoethylsulfonyl)-propanoylamino,4-(2-sulfatoethylsulfonyl)-butyrylamino or4-(2-chloroethylsulfonyl)butyrylamino; or when n is 2, is a radical ofthe formula: ##STR30## where L is C₂ -C₆ -alkylene or unsubstituted orhydroxysulfonyl-substituted phenylene and Y is as defined above, and therings A, B and C are unsubstituted or substituted by one or two halogenor hydroxysulfonyl groups; which method comprises: a) diazotizing anaminophenol of the formula (II): ##STR31## where the ring C is asdefined above, coupling with a coupling component of the formula (III):##STR32## where X and the rings A and B are each as defined above, andbefore, during or after the coupling reaction reacting with a copper ornickel salt, b) hydrolyzing the resulting formazan compound of theformula (IV): ##STR33## where cat⊕, X, Me and the rings A, B and C areeach as defined above, under acid or base catalysis, and c) reacting theresulting amino compound with a triazine of the formula (Va) or (Vb):##STR34## wherein Y is in either case as defined above, and Z¹ is C₁ -C₄-alkoxy, amino, mono- or di-(C₁ -C₄ -alkyl)amino, substituted C₂ -C₄-alkylamino, phenyl- or N-(C₁ -C₄ -alkyl)-N-phenylamino, wherein eachphenyl group is unsubstituted or substituted as defined above, or aradical of the formula: ##STR35## wherein L and Y are each as definedabove.
 2. The process as claimed in claim 1, wherein in formula (I), twoof the rings A, B and C are each monosubstituted by hydroxysulfonyl. 3.The process as claimed in claim 1, wherein Me is copper.
 4. The processas claimed in claim 1, wherein cat ⊕ is selected form the groupconsisting of hydrogen, lithium, sodium, potassium, unsubstitutedammonium, C₁ -C₂₀ monoalkyl-, C₁ -C₂₀ -dialkyl, C₁ -C₂₀ -trialkyl, C₁-C₂₀ -tetralkyl, benzyl-C₁ -C₂₀ -trialkyl-ammonium, pyrrolidinium,piperidinium, morpholinium, piperazinium, N-C₁ -C₂₀ -alkylipiperazinium;and pyrrolidinium, piperidinium, morpholinium, piperazinium, N-C₁ -C₂₀-monoalkyl and N,N-C₁ -C₂₀ -dialkyl.
 5. The process as claimed in claim1, wherein L is selected from the group consisting of (CH₂)₂, (CH₂)₃,(CH₂)₄, (CH₂)₅, (CH₂)₆, (CH(CH₃)CH₂), --CH (CH₃)CH(CH₃), 1,2-,1,3,1,4-phenylene and 4-hydroxysulfonyl-1,3-phenylene.
 6. The process asclaimed in claim 1, wherein said hydrolysis in step b) is effected at apH of from 1 to 3 and at a temperature of from 40° to 80° C. in anaqueous medium.
 7. The process as claimed in claim 1, wherein saidhydrolysis in step b) is effected at a pH of from 8 to 12 and at atemperature of from 40° to 80° C. in an aqueous medium.
 8. The processas claimed in claim 6, wherein said hydrolysis is complete after about0.5 to 2 hours of hydrolysis.
 9. The process as claimed in claim 7,wherein said hydrolysis is complete after about 0.5 to 2 hours ofhydrolysis.
 10. The process as claimed in claim 1, wherein Y ischlorine.